Gaseous fuel and air mixing venturi device and method for carburetor

Abstract

A gaseous fuel and air mixing venturi device adapted for retrofitting in a carburetor has a venturi body with a passage for air flow through the body, the passage having a throat of reduced cross-sectional area. The body has an axial fuel inlet port at a first end and fuel supply ports connected to the fuel inlet port and spaced around the throat for supplying fuel to the air flow passage for mixing with air flowing through the passage. The first end of the venturi body has mating seating formations for seating against corresponding seating surfaces of a gaseous fuel carburetor after removal of a spring mass air / fuel mixing section, and a fastener mechanism for releasably securing the venturi body in the carburetor, with the fuel supply port of the carburetor connected to the fuel inlet port of the venturi body.

Description

RELATED APPLICATION[0001]The present application claims priority to U.S. provisional patent application Ser. No. 60 / 722,113 entitled GASEOUS FUEL AND AIR MIXING ADAPTER DEVICE FOR CARBURETOR of concurrent ownership, filed on Sep. 30, 2005, which is incorporated herein by reference in its entirety.BACKGROUND[0002]1. Field of the Invention[0003]This invention relates generally to devices for mixing gaseous fuel and air in the correct proportions for combustion in a gas engine, and is particularly concerned with a venturi mixing device for replacing the spring mass, diaphragm actuator of existing gaseous fuel carburetors for natural gas engines and the like, and with a method of retrofitting a carburetor with such a device.[0004]2. Related Art[0005]The majority of gaseous fuel carburetors for internal combustion engines have an air / fuel mixing section which is comprised of a spring mass system. This has the potential to create unstable engine performance due to interaction with the ups...

AI Technical Summary

Benefits of technology

"The patent describes a gaseous fuel and air mixing venturi insert device that can be retrofitted into an existing gaseous fuel carburetor. This device replaces the conventional spring mass air / fuel mixing section of the carburetor and eliminates all moving parts. The insert device has a venturi body with a passage for air flow through it, with a throat portion of reduced cross-sectional area. The device has a fuel inlet port at the first end and a plurality of fuel supply ports connected to the fuel inlet port and spaced around the throat portion for supplying fuel to the air flow passage for mixing with the air flowing through the passage. The device is designed to maintain a near stoichiometric mixture throughout the operating range of the engine and can be easily installed in different models of carburetor. The venturi insert uses the existing mixture screw and butterfly throttle assembly of the carburetor and has a multitude of fuel inlet passages evenly dispersed throughout the low-pressure region of its throat, resulting in a more homogenous air / fuel mixture entering the engine. The device improves the performance of diaphragm operated carburetors and is relatively simple to install."

Problems solved by technology

This has the potential to create unstable engine performance due to interaction with the upstream pressure regulator or emissions control valve.

These new systems can respond very quickly and often create unstable interactions between the carburetor and the upstream fuel valve.

The diaphragm is typically an elastomer coated fabric and is susceptible to chemical and thermal degradation, rupture due to engine backfiring, abrasive damage, and the like.

The air / fuel mixing section of the carburetor also has sliding surfaces that are prone to wear.

Down time of an engine due to required maintenance in an industrial application, such as a pump on an oil pipeline, can result in the loss of thousands of dollars from lost production.

Another deficiency of known gaseous fuel carburetors is the limited ability to thoroughly mix the air and fuel together.

This makes it more difficult for the engine to completely burn all incoming fuel, which often results in higher exhaust emissions and a reduction in horsepower.

The limited number of existing gaseous fuel carburetor models and sizes may require the user to install a unit that is too large for the application.

A carburetor excessively large for an engine may cause starting troubles.

These mixers are not installed in the existing carburetor.

Instead, they replace the carburetor entirely, which often creates substantial installation difficulties and costs.

This requires major modifications to the engine's air intake system, which could result in thousands of dollars of lost production time.

Another major deficiency is that these mixers do not include a butterfly for controlling the air / fuel mixture to the engine.

Conventional retrofit difficulties increase significantly when the engine uses more than one carburetor, which is often the case.

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